BR112016007155B1 - SULFUR-FREE GAS ODORANT - Google Patents

Abstract

odorless gas without sulfur. the present invention relates to a sulfur-free odorant composition to be added to liquefied petroleum gas (lpg), in order to allow the user to feel any leak in the case of lpg leaks that may occur in the area of use.

Description

TECHNICAL FIELD

[001] The present invention relates to a sulfur-free odorant composition to be added to a liquefied petroleum gas (LPG | liquefied petroleum gas), in order to allow the user to feel any leak in the event of LPG leaks that may occur in the area of use.

PRIOR TECHNIQUE

[002] The odorization of gas has become a part of daily life, especially with the widespread use of natural gas in homes and industry, and measures to be taken in terms of safety are vitally important. Since natural gas that is not supplied for use (> 95% methane gas) is odorless, it cannot be felt by users in the event of any leak. In order to allow any possible leakage of natural gas to be detected before its concentration in the air reaches the lower limit of flammability, mercaptan compounds started to be added to natural gas since the 1940s. LPG is a by-product of the processes refining of natural gas and oil and is supplied from the points where said refining is carried out. The supplied LPG can comprise sulfur-containing compounds, in various types and proportions, according to the source of production. While sulphorous compounds can be contained in the LPG obtained from the refining of crude oil in various types and greater amounts depending on the refining process, they are generally less in LPG originating from natural gas. Based on this, the LPG has a characteristic odor profile due to the sulfur compounds contained. Depending on the amount of sulphorous compounds in the LPG, it may be necessary to odorize it additionally in certain cases. On the other hand, LPG that contains lower proportions of sulfur compounds is subjected to odorization. In the selection of odorants used in odorization, a criterion is applied, which is based on the fact that the odor of LPG, in terms of the nature of its odor, is unpleasant and distinct from odors that can be easily found in daily life. Currently, among the main odorization chemicals widely used in the LPG sector worldwide, sulfur compounds, such as methyl mercaptan, ethyl mercaptan, t-butyl mercaptan, n-propyl mercaptan, isopropyl mercaptan or tetrahydrothiophene, dimethyl sulfide and sulfide of diethyl are included. In addition to the nature of the odor, other important criteria used in the selection of said odorants are the intensity of the odor and the physical and chemical characteristics of the odorants. LPG is a fuel in several areas, which is used in heating, cooking, lighting, as a vehicle fuel and as a propellant in perfumes. Most of these areas of use require the LPG, which is produced for the consumer, to be odorized.

[003] An odorant commonly used in the LPG and Ethyl Mercaptano sector (EM | Ethyl Mercaptan), which contains sulfur at a level of 52% in its molecular structure. In order to comply with the TS EN 589 standard condition that stipulates that 'The odor of the gas must be specific (characteristic and unpleasant) and its odor must be detectable when its concentration in the air is less than 20% of its lower flammability limit. ', the amount of ME dosed in the LPG is approximately 20 ppm, depending on the limit of the description of the odor and volatility of EM. The lower and upper explosion limits of the Liquefied Petroleum-air mixture are 1.55% and 9.6%, respectively. This 20 ppm sulfurous EM compound added additionally in LPG increases the sulfur content of the LPG by approximately 10 ppm. As a result of this addition of EM, the sulfur content in 1 ton of LPG is increased by 10 g. Considering 3.5 million tons of the LPG market, this value corresponds to approximately 35 tons of elemental sulfur content. As a result of converting 35 tons of sulfur into SO2 gases in the engine and combustion systems, SO2 emissions increase.

[004] In the automotive sector, for the purpose of converting environmentally hazardous exhaust gases that are released during fuel consumption, into less dangerous gases through oxidation, catalytic converters are used in vehicles. Due to the susceptibility of catalytic substances (Pt-Rh / CeO2-Al2O3) used in catalytic converters for sulfur, exhaust gases with a high sulfur content increase the amount of dangerous gas released into the atmosphere by negatively affecting the oxidation performance of catalytic converters . Such effect of sulfur on catalytic substances is not permanent, and with a decrease in the sulfur content of the fuel used, the negative effect on the oxidation performance disappears. In this regard, decreasing the sulfur content of LPG used as a car gas will not only result in a decrease in SO2 emissions, but also in the emission quantities of all dangerous exhaust gases emitted into the environment during the consumption of automobile gas. .

[005] Liquefied Petroleum Gas means liquid gas that can be converted into a liquid phase generally at 20 ° C and under pressure of 3.5 Bars. Basically, it consists of n-propane, propylene, n-butane and butylene. With a narrower description, it is a liquid gas consisting of mixtures of n-propane and n-butane. Such a mixture may contain low amounts of unsaturated hydrocarbons and / or branched hydrocarbons such as propylene, isobutane, 1-butylene, cis-2-butylene, trans-2-butylene or isobutylene.

[006] Liquefied Petroleum Gas is generally transported without undergoing any odorization process. The odorization process is carried out in the storage facilities. During the odorization process, the storage tank is supported with nitrogen against risk of explosion. According to TS TSE / TS 8038 Standard, the amount of odorant required to be added to Liquefied Petroleum Gas is calculated as follows: when the gas concentration in the air is equal to 20% of the lower explosion limit, in order to allow Once the odor reaches the warning level, the concentration (C) of odorant required in Liquefied Petroleum Gas can be calculated in general terms by the following formula, in mg / m3: C = (K.100) / (0.2 .APS).

[007] Characterized by K defining the odor detection limit. The K values for certain odorants are as follows:

[008] State of the art patent document No. US 2004/0031314 A1 that uses ethyl selenol is used to odorize hydrogen gas, which is extremely flammable. Its extremely high odor power is effective even at very low concentrations.

[009] State of the art patent application No. US2006 / 0009372 discloses mixtures of sulfur-containing acrylic acid alkyl esters. JP-B 51-034841, JP-B 51-021402 and JP-A 55056190 disclose the use of mixtures containing ethyl acrylate, while DE-A 3151215 discloses the use of mixtures containing isovaleraldehyde.

[010] US2006 / 0009372 and US 2,430,050 and DE-A 1983 7066 disclose the use of phenol-derived antioxidants for odorants containing mercaptan or alkyl acrylate.

[011] State of the art patent application No. DE 19837066 A1 discloses sulfur-free and nitrogen-free odorous compositions for hydrogen gas, comprising ethyl acrylate, methyl acrylate, propionaldehyde and / or butyraldehyde, and acetophenone (see page 8 , line 3 to page 9, line 6; examples 1 to 3); according to that request, the presence of acetophenone intensifies the warning odor on acrylate mixtures.

[012] It is seen in prior art documents that sulfur compounds are often used in liquefied petroleum gas compositions. Sulfur compounds are dangerous to human health, the environment and machine parts. When using odorants that contain sulfur compounds and such odorants are used with LPG, the emissions that arise from the consumption of LPG such as bottled gas and automobile gas have adverse effects on humans and other living creatures in terms of the aspects mentioned below. With the use of an inventive sulfur-free odorant, these adverse effects will be eliminated.

DANGERS TO HUMANS AND OTHER LIVING CREATURES

[013] Sulfur-containing compounds, when exposed to the respective high amounts, can cause damage to the cell structure of living creatures. Thiol transfer, which catalyzes the substitution reaction with glutathione and shows a high degree of activity in organs and tissues, is affected in the first order by the toxicity of dialkyl disulfide (Lillig and Holmgren, 2007). The reaction mechanism is very important because it is released with the free radical medium with excessive and high reactivity that can initiate the redox cycle in the macromolecules of the tissue or in the places they form (Figure 1).

[014] The mechanism of dialkyl disulfide free radical formation and the reaction steps of the redox cycle are shown below (Munday and Manns, 1994). The first product of the thiol transfer substitution reaction is an alkyl mercaptan (1); after being ionized, it undergoes a single electron oxidation (2) and the intermediate free radical phase occurs. This intermediate product is toxic and is a product of constant hydroxyl radical and other examples of reactive oxygen can maintain the redox cycle (3, 4, 5, 6) and they cause oxidative stress and tissue damage in the places they form.

[015] 2 GSH + RSSR θ GSSG + 2 RSH (1)

[016] RSH θ RS- + H + (2)

[017] (Hb) Fe3O2 * - + RS- + 2H + ^ (Hb) Fe3 + RS * + H2O2 (3)

[018] RS * + RS-θ (RSSR) * - (4)

[019] (RSSR) • - + O2 ^ RSSR + 02 * - (5)

[020] RSH + O2 * - + - H '^ RS * + H2O2 (6)

[021] Long chain lengths in a molecule decrease the stability of the radical, thereby reducing the rate of oxidation (Munday, 1989). In addition, the reactivity and toxicity of alkyl disulfites are reduced as follows due to the effect of steric factors on thiol transfer activity: n> sec> tert. According to this information, DMDS is the most reactive member of the homologous sequence in terms of chain length and branching.

[022] Additionally, Fe and its oxides cause damage to the storage tanks by showing the following reactions with H2S.

[023] Fe + H2S ^ FeS + H2 (7)

[024] Fe2θ3 + 3H2S ^ 2FeS + 3H2O + S (8)

[025] 2Fe (OH) 3 + 3H2S ^ 2FeS + 6H2O + S (9)

[026] Fe (OH) 3 + 3H2S ^ Fe2S3 + 6H2O (10)

[027] Fe3O4 + 4H2S ^ 3FeS + 4H2O + S (11)

ACID RAIN

[028] The combustion of sulfurous fossil fuels is the main source of SOx. The formation of SOx results from the emergence of SO2 outside combustion, in a proportion between 97% and 99%. The remainder is mainly sulfur trioxide (SO3). This compound available in atmospheric water vapor quickly changes to H2SO4. When in sufficient concentrations, SO2 and H2SO4 are dangerous to the respiratory system. In addition, SO2 is also toxic to plants (U.S. EPA, 1999).

CATALYTIC CONVERTER INTOXICATION

[029] Sulfur poisoning is a complicated event that alters the structural, morphological and electronic characteristics of the catalyst (Rodriguez & Hrbek 1999). Sulfur negatively affects the oxygen activity and storage capacity of the catalyst (Boaro et al. 2001, Yu & Shaw, 1998). The presence of sulfur can cause the formation of new inactive compounds on the surface of the catalyst. In addition, it can also cause structural changes in the catalyst (Yu & Shaw, 1998).

[030] Depending on the temperature and partial pressure of the oxygen, the sulfur contained in the exhaust gas can be converted into sulfate, sulfite or oxysulfites by the catalyst (Karjalainen et al. 2005). At temperatures below 300 ° C, these oxides are absorbed by the active surfaces on the catalyst surface and reduce the active surface, so that the effectiveness of the catalyst decreases. Under reducing conditions, sulfur forms H2S and intoxicates metal surfaces and negatively affects hydrocarbon oxidation (Rabinowitz et al., 2001). In the case of a rich mixture of SO2, sulfur deactivation is more important in the presence of NOx, and even at 1000 ° C, very stable sulfates can form, without being attacked by the reducing agents, especially in the absence of water (Fridell et al. 2001, Mahzoul et al. 2001).

BRIEF DESCRIPTION OF THE INVENTION

[031] The present invention relates to an odorizing gas composition, comprising methyl acrylate and / or ethyl acrylate and / or isovaleraldehyde and at least one selenium compound used in the odorizing liquefied petroleum gas, characterized by said selenium compound being selected from the group consisting of dimethyl selenide, dimethyl diselenide, diethyl selenide, diphenyl selenide, diphenyl diselenide or ethyl selenol.

OBJECTIVE OF THE INVENTION

[032] An object of the present invention is to provide an odorant composition, consisting of isovaleraldehyde and / or methyl acrylate and / or ethyl acrylate and, preferably, at least one selenium compound to odorize liquefied petroleum gas, which it is sulfur free and does not involve the adverse effects caused by sulfur compounds. Such adverse effects are environmental pollution, corrosion of materials and sulfur-related poisoning from the catalyst converter.

[033] Another objective of the invention is to increase the efficiency of the combustion reactions of the fuel with the addition of selenium compounds in the odorant composition used in the odorization of liquefied petroleum gas and to prevent the formation and accumulation of soot in the cylinder blocks of the motor.

DESCRIPTION OF THE FIGURES Figure 1 is the reaction step in the In Vivo metabolism of dialkyl disulfites. DESCRIPTION OF THE INVENTION

Fórmula 1

Fórmula 2

Fórmula 3[034] The odorant composition disclosed in this invention consists of different concentrations of isovaleraldehyde, methyl acrylate, ethyl acrylate and selenium compounds; preferably, composed of dimethyl selenide. In particular, the composition of this invention is free of sulfur. The odorants that contain sulfur compounds and SO2 gases resulting from the respective combustion in the vehicle's engine cylinders and gas ovens, cause air pollution, which can result in respiratory tract diseases. When exposed to high amounts, sulfur compounds can result in molecular damage especially to living creatures. For vehicles that use Liquefied Petroleum Gas, the sulfur compounds cause corrosion and accumulation in the metal and plastic parts, which shorten the life of the material. On the other hand, since the inventive sulfur-free odorant has an oxygenated organic compound structure, the CO2 and H2O resulting from combustion do not harm human health. With the present invention, isovaleraldehyde, ethyl acrylate and methyl acrylate compounds together with selenol compounds are used instead of sulfur compounds. Selenol compounds such as dimethyl selenide compound contained in that invention increase the effectiveness of combustion reactions by inhibiting the aromatization reactions that cause coke formation during combustion. The selenol compounds added to the LPG as an odorant prevent the formation and accumulation of soot in the engine cylinder blocks during combustion reactions. The chemical structures of methyl acrylate, ethyl acrylate and isovaleraldehyde are given in Formula 1, Formula 2 and Formula 3, respectively.

Formula 1

Formula 2

Formula 3

Fórmula 4[035] The selenium compounds to be used in the present invention are selected from the dimethylselenide shown in Formula 4;

Formula 4

Fórmula 5[036] Dimethyl diselenide shown in Formula 5,

Formula 5

Fórmula 6[037] Diethyl selenide shown in Formula 6,

Formula 6

Fórmula 7[038] Diphenyl selenide shown in Formula 7,

Formula 7

Fórmula 8[039] Diphenyl diselenide shown in Formula 8, or

Formula 8

Fórmula 9[040] ethyl selenol (Formula 9) shown in Formula 9.

Formula 9

Tabela 1[041] In the illustrative applications of the invention, the selenium compound is preferably selected as dimethyl selenide. In Table 1, the physical characteristics of the compounds of methyl acrylate, ethyl acrylate, isovaleraldehyde and dimethyl selenide are given.

Table 1

[042] Isovaleraldehyde is available in nature in more than one hundred and eighty plants, including foods such as bananas, apples, carrots, cocoa and coffee. In addition, in the food industry, the aroma of these plants is also used in the production of amino acids in medical applications. It is used in the pharmaceutical industry for antiviral protection and drugs against central nervous system disease and as an excipient.

[043] The inventive odorant consists of different concentrations of chemical mixtures of isovaleraldehyde, methyl acrylate, ethyl acrylate and dimethyl selenide. In that regard, the odorant is suitable for Liquefied Petroleum Gas chemically and physically and is completely sulfur-free. Therefore, air pollution arising from sulfur and diseases of the resulting respiratory tract, as well as problems arising from the accumulation of sulfur in vehicles will be eliminated.

[044] Selenium forms weaker bonds than sulfur. Compared to sulfur compounds, these bonds break more easily into selenium compounds and they release. Selenium oxidizes easily in Se (IV).

[045] Organoselenium compounds can be easily attacked by nucleophiles. This prevents soot accumulation over a long period of time by delaying polymerization for which heavy hydrocarbon structures, which are possibly available in LPG and cause serious problems in engine parts depending on long-term use, can be subjected to over time depending on combustion.

[046] The carbon-selenium bonds of the compounds of SeC, H2Cse and H3CseH are defined as 1,676 Â, 1,756 Â and 1,959 Â, respectively (Determan and Wilson, 2013). However, the carbon-sulfur bond that is approximately 1.39 to 1.40 Â in sulfur compounds makes the structure more robust (Schreiner et al., 2009). The energy of 234 kJ / mol is required to break the C-Se bonds, while the CS bonds require an energy level of 272 kJ / mol (Krief, 1988; Patai et al., 1986; Paulmier, 1986; Freudendahl , 2009 and Wallschlager, 2010).

[047] The illustrative compounds of this invention are given below.

Claims (4)

1. “SULFUR-FREE GAS ODORANT COMPOSITION”, for liquefied petroleum gas, characterized by comprising ethyl acrylate, isovaleraldehyde and dimethyl selenide. 2. “SULFUR-FREE GAS ODORANT COMPOSITION”, according to claim 1, characterized by comprising methyl acrylate. 3. "SULFUR-FREE GAS ODORANT COMPOSITION", according to claim 1, characterized by comprising 0 to 50% methyl acrylate, 10 to 40% ethyl acrylate, 25 to 75% isovaleraldehyde, from 2 to 10% of dimethyl selenide by weight. 4. "SULFUR-FREE GAS ODORANT COMPOSITION", according to claim 1, characterized by comprising 10 to 40% ethyl acrylate, 25 to 75% isovaleraldehyde, 2 to 10% dimethyl selenide in Weight.

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